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Measuring & Mapping

Where, how far, and how much? People have invented an astonishing array of devices to answer seemingly simple questions like these. Measuring and mapping objects in the Museum's collections include the instruments of the famous—Thomas Jefferson's thermometer and a pocket compass used by Meriwether Lewis and William Clark on their expedition across the American West. A timing device was part of the pioneering motion studies of Eadweard Muybridge in the late 1800s. Time measurement is represented in clocks from simple sundials to precise chronometers for mapping, surveying, and finding longitude. Everyday objects tell part of the story, too, from tape measures and electrical meters to more than 300 scales to measure food and drink. Maps of many kinds fill out the collections, from railroad surveys to star charts.

Design features suggest that this compass may date from the third quarter of the 18th century. The bar holding the vertical sights is straight and narrow. The needle rim is graduated to single degrees, and numbered in quadrants from North and South. The face reads clockwise. And, with an extra needle and scales at North and South, the compass can serve as a clinometer for measuring angles of elevation.

This compass may date from the fourth quarter of the 18th century. Although the bar holding the vertical sights is straight and narrow, the face reads counterclockwise. The needle rim is graduated to single degrees, and numbered in quadrants from North and South.

The “C.G. King Boston” signature refers to Charles Gedney King (1808-1858), a mathematical instrument maker who apprenticed with his father, Gedney King, and traded under his own name after his father’s death in 1839. C. G. King showed his instruments at fairs sponsored by the Massachusetts Charitable Mechanics Association in the 1840s and 1850s, and took home several silver medals.

King also announced he "Is now manufacturing and has for sale the largest assortment of Mathematical, Nautical, Engineers, Surveyors and Drafting Instruments to be found in the city." Moreover, the engineers’ and surveyors’ instruments manufactured in the King establishment, "are divided upon a new Engine, made expressly for the purpose, the performance of which, for the accuracy of its division, cannot be surpassed, if equalled, by any Engine in the Country."

The rim of this example is graduated to 30 minutes. There are two level vials on the south arm.

This resembles Gurley’s small vernier compass but has no vernier mechanism. The outer rim of the box is graduated to single degrees, and numbered every 10 degrees. The instrument can be used with the folding sights raised to the vertical, or with the sighting bar. In the latter case, the folding sights are folded towards each other, to form a tent, and the sighting bar attached on top. The sighting bar is equipped with a vertical circle graduated to single degrees. This form has not been found listed or described in any Gurley trade literature. The "W. & L. E. Gurley, Troy, N.Y." inscription was engraved by machine, dating it to after 1876.

W. & L. E. Gurley submitted this instrument to the U. S. Patent Office in support of their application for a patent describing an Improvement in Telescope Attachments for Surveyors’ Compasses. The patent (#205,742) was issued on July 9, 1878. The Patent Office transferred this model to the Smithsonian in 1926.

The basic instrument is a standard small compass with a north-south level on the north arm, and an east-west level and an outkeeper on the south arm. The hand-engraved signature indicates that the compass was made before the middle of 1876. The telescope, which attaches to one of the sight vanes, was presumably made shortly before the patent application was submitted in June 1878. The signature reads "W. & L. E. Gurley" and "Troy, N.Y."

This compass, with its accompanying Jacob staff, is said to have been used in the Peirce Mill area of what is now Washington, D.C., in the 1790s, and the design seems appropriate for that period. The needle rim is graduated to single minutes and numbered clockwise from north. The face seems to have been copied from that of a nautical compass: it reads clockwise, and is numbered in quadrants from north and south.

This compass is marked "S. Kern Inventor" and "J. S. Danner Maker, Middletown, Va." On July 31, 1846, Samuel Kern of Strasburg, Va., obtained a patent (#4,675) for an instrument meant to be "at once cheap and efficient, enabling one to use it as a compass for running lines, or for leveling, as may be required." A trough compass, level vial, and outkeeper are inset into the face. The edge of the face is graduated to 30 minutes, and numbered in quadrants from north and south. Jacob Sensensy Danner (1807-1877) lived in Middletown, Va., and made instruments for surveyors.

This compass is more British than American, and in Britain it would have been referred to as a "circumferentor." The face reads clockwise. The needle rim is graduated to single degrees, and numbered counterclockwise from north. The "Messer London" signature refers to Benjamin Messer, an instrument maker who was in business during the years 1789–1827.

James Prentice (1812–1888) was born in London and trained as an instrument maker. He began in business in New York in 1842, importing and manufacturing mathematical instruments. Later advertisements mention optical, meteorological, and electrical apparatus as well. The firm became James Prentice & Son in 1883, and James Prentice & Son Company in 1897.

The compass marked "J. Prentice, 66 Nassau St., N. Y." was made around 1860, when Prentice was working at this address. The rim is graduated to 30 minutes. There is a north–south level vial on the north arm, and an east–west level on the south arm.

This compass has a 4-inch needle (the same "as is furnished with Gurley Precise Transits"), needle release, two folding sights, two levels on the face, and a jacob staff mounting. Gurley introduced this form in the 1920s, describing it as "an excellent and portable instrument for running lines through woods." This example belonged to the University of Missouri at Columbia. New, it cost $35. The signature reads "W. & L. E. GURLEY TROY, N.Y. U.S.A."